Triazolyl derivatives endowed with a fungicidal activity are known in literature; for example, British patent application No. 1,511,956 (Imperial Chemical Industries) described triazolyl-diketo-derivatives of general formula: ##STR2## in which R.sup.1 and R.sup.2, like or unlike each other, may be cycloalkyl, alkyl or phenyl, these groups being optionally substituted.